On July 6

2017

a power oscillation occurred in Silin Hydropower Plant during the period of No. 2 generator increasing its output power and the plant voltage dropped continuously. Based on the on-site record curve and simulation by BPA software and RTDS

the causes of power oscillation are analyzed in detail

and the scene of the power oscillation is reproduced. In response to the problems including that the generator's reactive power mode is set incorrectly and the power system stabilizer(PSS)has some defect in low frequency band because of measurement errors in rotator speed

the application principle of the plant reactive power control mode is proposed and the damping character is promoted by optimizing PSS's ramp function setting. The scheme has been put into operation in Silin Hydropower Plant after RTDS and on-site test

and it shows that the damping characteristic of the plant is improved effectively. The suggestions for improvement of PSS's setting criterion are proposed combined with the on-site test.